The present teachings are predicated upon providing an improved parking brake system for a vehicle. Parking brake systems typically include one or more brake pads that are moved against a rotor to generate a parking brake force necessary to restrain the vehicle from moving. The parking brake force may be generated by electromechanical application of a piston. On a light vehicle platform, passenger cars and light duty trucks may include rear, single piston calipers, which can adequately decelerate a vehicle. In the case of as non-braking condition (i.e., when the vehicle is parked), a parking brake system may utilize the already existing service brake caliper structure (i.e. the single piston) to restrain movement of the vehicle. The brake pads may be moved against the rotor with a single electromechanical gear and a linkage (i.e., a spindle and nut assembly, for example) that is already integrated with the service brake caliper and designed to utilize the already existing single piston service brake caliper.
Heavy duty full size trucks, vans and SUVs may include rear, two-piston calipers to decelerate the vehicle. In the case of a non-braking condition (i.e., when a vehicle is parked), it may be desirable to have a parking brake system that utilizes the existing service brake caliper structure that moves the brake pads via an electromechanical gear and linkage (i.e., a spindle and nut assembly, for example) to generate a parking brake force. It may further be desirable to provide a parking brake force utilizing the two existing pistons and linkages (i.e., a spindle and nut assembly, for example) on the existing rear caliper to provide increased parking brake forces for heavy duty and full size truck applications, for example. The parking brake system of the present teachings aims to utilize an existing structure of a service brake caliper to provide a parking brake system in order to reduce and/or maintain vehicle packaging, costs, or both.